EXTRACTION  AND  UTILIZATION 


OF 


UTAH  SULFUR 


by 


J O H N SHED  D P R ESCOTT 


Til  ESIS 


FOR  THE 

DEGREE  OP  BACHELOR  OP  ARTS 

IN 

CHEMISTRY 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 


UNIVERSITY  OP  ILLINOIS 
1921 


UNIVERSITY  OF  ILLINOIS 


UJ 

1/0 

I92__l 

THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 

JOHN  _ SHEDD_ PRESCOT T 

ENTITLED 1?  _ AND_  _U  T_I  LIZ ATI  ON  _ OP  _ U T AH  _ pUpfUH 


IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 
DEGREE  OF  Bachelor  of  Arts  in  Chemist  ry_ 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/extractionutilizOOprec 


1 


THE  EXTRACTION  AND  UTILIZATION  OP  UTAH  SULFUR. 
TABLE  OF  CONTENTS. 

PAGE. 

I.  INTRODUCTION  2. 

II.  HISTORY  SHOWING  NECESSITY  FOR  RESEARCH.. 4. 

III.  GEOLOGICAL  STUDY, AND  ANALYSES 6. 

IV.  THE  LEACHING  PROCESS 11. 

Figure  1 13. 

Table  1 15. 

V.  THE  ROASTING  PROCESS 20. 

VI.  SUMMARY  24. 

VII.  UTILIZATION  26. 


THE  EXTRACTION  AND  UTILIZATION  OP  UTAH  SULFUR 


"The  very  art  of  chemical  engineering  has  been  re- 
volutionized from  the  method  of  ore  grading  to  the  electric 
furnace  or  the  modern  electrolytic  plant.  From  the  first 
construction  of  machinery  to  the  final  loading  of  the  finish- 
ed products  on  the  car,  electricity  is  everywhere  serving 
faithfully  in  plants  that  seem  to  grow  over  night."  This 
quotation,  which  appeared  in  an  advertisement  of  the  General 
Electric  Company  in  a recent  scientific  magazine,  prompted  the 
suggestions  which  have  been  made  in  this  paper  regarding 
the  operations  of  the  Utah  Sulfur  Corporation. 

Thus,  the  problem  faced  by  this  corporation  at  the 
present  time,  that  of  determining  whether  or  not  the  sulfur 
in  the  Utah  deposit  can  be  profitably  extracted,  and  thence 
determining  the  best  method  by  which  to  remove  the  sulfur 
from  the  ore,  has  been  approached  from  the  standpoint  of  the 
chemical  engineer. 

The  process  of  determining  the  best  method  has  en- 
volved  a study  of  all  the  methods  used  up  to  the  present  time 
with  an  effort  to  find  a better  method,  if  possible.  And  in 
order  that  the  final  process  decided  upon  might  be  as  nearly 
perfect  as  possible,  it  was  necessary  to  study  the  ore  deposits 
both  from  the  standpoint  of  the  geologist  and  the  chemist. 

Thus  th©  methods  used  at  the  present  time  by  the  producers 
of  sulfur  in  our  southern  states--  Louisana  and  Texas  ( 1 . ) — 

(1)  U. S. Geological  Survey,  July  1918, 581R. 


. 


- 

. ■ 


3. 


- and  in  foreign  countries--  Sicily  and  Japan--(l.)  have 
been  studied.  In  each  case  an  endeavor  has  been  made  to 
relate  these  methods  to  the  work  upon  the  Utah  ore  after  a 
study  of  the  advantages  and  disadvantages  of  each  process. 

Under  the  topic  " Utilization  " is  included  an  out- 
line of  the  extent  of  the  market  for  the  various  forms  of 
sulfur  products,  including  present  prices  and  the  probable 
fluctuations . 


\ 

/ 


vol.  6, 


(1.)  Mineral  Industry, 


1900,  Page  592. 


- - ■ - 

. 


.-fry 

. - ; 


1 


4 


HISTORY  OF  THE  WORK  ON  THE  UTAH  DEPOSIT  SHOWING  THE  NECESSITY 
OF  RESEARCH. 

The  sulfur  deposit , which  is  located  at  Morrissey  Utah, 
some  two  hundred  miles  south  of  Salt  Lake  City,  has  been  work- 
ed for  a period  of  about  thirty  years  at  irregular  intervals. 
In  all  cases,  including  the  present  workings,  it  appears  that 
the  methods  have  been  very  crude  and  unscientific,  and  especi- 
ally before  the  work  was  taken  over  by  the  Utah  Sulfur  Corp- 
oration it  was  evidentally  only  possible  to  work  the  deposit 
during  periods  of  high  prices. 

The  managers  of  the  older  companies  did  not  operate 
the  mine  with  any  ideas  of  sound  business.  They  simply  ex- 
tracted the  high  grade  ore  wherever  it  could  be  found,  and 
piled  the  lower  grade  ores  and  the  overburden  to  one  side. 

This  process  of  course  made  it  necessary  to  rehandle  the  so 
called  waste  over  and  over  again  and  finally  resulted  in  the 
closing  of  the  mine  after  a good  part  of  the  higher  grade  ores 
had  been  removed.  And  because  of  these  previous  workings,  the 
mine  is  at  the  present  time  filled  with  what  would  previously 
have  been  considered  low  grade  ore.  The  old  method  method 
of  recovering  the  sulfur  is  of  course  the  cause  for  this 
condition.  ( 1. ) 

In  most  cases  vertical  cast  iron  retorts  were  used. 
These  retorts  were  ten  feet  high  and  four  feet  in  diameter, 
and  were  filled  with  the  ore  and  heated  with  steam.  A por- 
tion of  the  sulfur  melted  and  was  drawn  off  at  the  bottom  of 

(1.)  Report  of  W.  Darrah  upon  the  Utah  Sulfur  Corp. 

March,  1,  1921. 


I 


•' 


- 


K . • 


■ .■ 

f •- 


‘ i L . 


" ■ 


5. 


the  retort.  From  the  tailings  at  present  at  the  mine  which 
average  about  thirty  percent  of  sulfur,  it  appears  that  from  a 
sixty  percent  ore  it  was  only  possible  to  extract  one  half  of 
the  available  sulfur,  while  from  a thirty  five  percent  ore  only 
about  fifteen  percent  of  the  sulfur  was  extracted.  For  this 
reason  the  steam  re tor ting  method  has  not  been  considered  in 
any  way  feasible  especially  considering  the  fact  that  piles  of 
tailings  have  accumulated  from  these  previous  workings  which 
make  it  essential  that  a much  more  efficient  method  be  used 
in  order  that  the  mine  may  be  successfully  operated.  Never- 
theless, the  method  has  been  reviewed  in  the  hope  that  it  might 
suggest  some  better  method,  and  also  that  the'  difficulties  en- 
countered might  be  noted  so  that  these  same  difficulties  might 
be  avoided  in  considering  a new  method.  In  addition  to  this 
method  which  consists  in  melting  the  sulfur  out  of  the  ore;  the 
leaching  process, which  consists  in  dissolving  the  sulfur  out 
of  the  ore  with  carbon  disulfide  and  then  evaporating  the  latter 
leaving  the  sulfur,  has  been  studied  in  detail.  This  method 
makes  the  total  process  much  more  difficult  in  that  it  neces- 
sitates the  presence  of  a plant  for  the  producing  of  the 
solvent.  This  process  has  however  been  investigated  in  an 
endeavor  to  relate  this  method  to  the  production  of  flowers 
of  sulfur  by  the  use  of  a furnace  similar  to  those  used  by 
the  producers  of  carbon  disulfide  in  the  electric  furnaces  at 
Pen  Yan,  Pennsylvania.  (1.) 

(1.)  Manufacture  of  Electric  Furnace  for  the  Product- 
ion of  Carbon  Disulfide.  E.R. Taylor,  A.M.E.537.06 

Trans  Am.  Electrochem  Soc . ,16,229-234. 


6. 


A GEOLOGICAL  STUDY  OF  THE  ORE;  PREVIOUS  ANALYSES  OF  THE  ORE; 
AND  ANALYSIS  CONDUCTED  IN  CONNECTION  WITH  THIS  PROBLEM. 

I. 

The  sulfur  in  all  forms  of  the  ore  exists  in  the  free  state 
physically  mixed  with  earth,  lime  and  volcanic  ash.  (1.) 

There  are  three  distinct  types  of  ore  in  this  deposit. 

1. )  The  most  common  ore  consists  of  a soft  light  gray 
rhyolite  carrying  from  ten  to  fifty  percent  of  yellow  sulfur 
distributed  in  a lamillar  manner  throughout  the  mass. 

2.  ) Next  in  importance  is  that  ore  made  up  of  yellow 
fairly  dense  semi-crystaline  sulfur  mass  intermixed  with 
rhyolite  and  earth.  The  quantity  of  sulfur  in  this  type 

of  ore  is  relatively  high  running  from  fifty  to  as  high  as 
eighty  percent.  This  was  the  type  of  ore  that  was  preferred 

by  the  early  operators  of  the  mine. 

3. )  The  third  type  is  somewhat  similar  to  the  prev- 
ious, but  it  is  colored  grayish  black  by  the  presence  of 
upwards  to  twenty  percent  of  volcanic  ash  containing  mangan- 
ese and  iron. 

According  to  a recent  report,  it  is  estimate:  that 
the  mine  at  present  contains  in  the  neighborhood  of  200,000 
tons  of  available  sulfur  which  would  allow  the  mine  to  be 
worked  over  a period  of  from  ten  to  fifteen  years  even  if 
the  daily  output  of  the  plant  should  reach  as  high  as  50 
tons  per  day.  Also  it  is  quite  interesting  to  note  that 

(1.)  U.S. geological  Survey  Bull. 515,  485-489. 


, 

J . . ' ^ ■ — ■ r ■ 

. J 


■*  * ' * 


'■j 


wi  V 


7. 


gases  are  still  escaping  which  deposit  sulfur;so  that  there 
is  a possibility  that  the  mine  might  be  worked  for  a longer 
period. 

II. 

A recent  analysis  of  samples  taken  from  all  parts  of  the  mine 
have  given  an  average  of  about  thirty  percent  sulfur.  (1.) 

This  approximately  represents  the  average  richness  of  the 
ore  remaining  in  the  mine.  This  of  course  being  true  only  in 
the  event  that  the  samples  were  representative.  However,  in 
any  case,  the  point  to  be  emphasized  is  that  any  method  under 
consideration  must  be  able  to  efficiently  extract  the  sulfur 
from  an  ore  containing  thirty  percent  or  less  of  sulfur. 

From  all  the  analyses  that  have  come  to  view,  none 
have  been  found  that  report  the  presence  of  arsenic  or  anti- 
mony. Since  these  substances  are  very  undesirable  in  a sulfur 
ore  because  of  the  difficulty  experienced  in  their  removal 
from  the  final  product,  the  value  of  the  ore  is  greatly  in- 
creased by  their  absence.  In  all  reports  the  ore  is  represent' 
ed  as  a mixture  of  free  sulfur  and  silica  and  lime  with  very 
small  percentages  of  metallic  ingredients. 

III. 

The  work  herein  described  has  been  confined  entirely 
to  the  second  type  of  ore.  Approximately  eighty  pounds  of 
ore  of  this  type  was  received  from  Utah  from  which  represent- 
ative samples  amounting  to  twenty  pounds  were  chosen.  This 
(1.)  Report  of  W.  Darrah,  March  1921. 


' - 


5 


; ' r 


8. 


weight  was  ground  to  about  the  size  of  a pea  and  was  then 
quartered  in  the  usual  manner  until  a representative  sample 
of  about  one  half  pound  was  obtained.  This  was  then  ground 
in  a morter  until  it  could  be  sifted  through  an  eighty  mesh 
seive.  The  remainder  of  the  twenty  pounds  was  then  retained 
and  has  been  used  in  all  the  extraction  methods. 

Using  the  finely  divided  ore  in  all  determinations, 
the  ore  was  next  analysed  fDr  available  sulfur  in  case  the 
ore  was  heated  to  vaporize  the  sulfur,  for  available  sulfur 
by  means  of  extraction  with  carbon  disulfide;  for  silica, 
metallic  oxides,  and  the  lime  and  calcium  sulfate  were  deter- 
mined by  difference.  A check  was  later  taken  by  direct  anal- 
ysis for  sulfate. 

In  the  first  case,  as  also  in  the  subsequent  analyses, 
a one  gram  sample  was  used.  This  sample  -was  then  heated  in 
a number  one  crucible  until  there  was  no  further  loss  in 
weight.  The  loss  in  weight  represented  directly  in  percent- 
age the  amount  of  sulfur  in  the  ore.  All  values  for  this 
determination  checked  to  within  .2  of  60^. 

In  the  deter  mination  of  available  sulfur  by  the 
leaching  method,  a one  gram  sample  was  placed  in  a Gooch 
crucible  which  had  previously  been  washed  with  carbon  di- 
sulfide in  addition  to  the  usual  method  of  preparation.  The 
solvent  was  then  run  through  the  filter  until  upon  drying 
the  filter  there  was  no  further  loss  in  weight.  The  avail- 
able sulfur  by  this  method  represented  the  more  true  value 


9. 


since  in  this  case  there  was  no  possibility  of  the  ash 
changing  in  composition  as  it  would  tend  to  change  when  heated. 
The  small  difference  in  the  two  determinations  would  indicate 
that  there  is  very  little  calcium  carbonate  in  the  ore.  It 
appears  therefore  that  the  calcium  in  the  ore  is  mostly  in 
the  form  of  the  sulfate  and  oxide.  The  value  for  this  deter- 
mination was  59$. 

In  determining  the  percent  of  silica,  the  sample  was 

first  heated  to  drive  off  the  sulfur. The  samples  of  ash 

from  the  first  determination  of  sulfur  may  be  conveniently 
used  for  this  purpose.--  This  ash  was  then  fused  with  a 
sufficient  weight  of  sodium  carbonate,  and  the  mass  extract- 
ed with  water  and  dilute  HC1.  By  repeated  evaporations,  the 
silica  was  converted  to  the  insoluble  form,  and  the  percent 
was  determined  by  noting  the  loss  of  weight  when  the  ignited 
residue  was  treated  with  HF  and  H2S04-  in  a platinum  crucible. 
This  determination  gave  29  as  the  percentage  of  silicon  di- 
oxide . 

The  heavier  oxides  were  determined  from  the  filtrate 
from  the  silica  determination  by  precipitation  with  NH40H 
according  to  the  standard  method. 

These  values  give  by  difference  the  percentage  of 
lime  and  calcium  sulfate  as  10. 3.  As  indicated  by  the 
difference  in  the  two  determinations  of  sulfur,  this  repre- 
sents probably  2.3 $ CaC03  and  8.0$  CaS04.  These  last  two 
figures  being  true  in  the  case  that  the  1$  difference  in 
the  sulfur  determinations  represented  a loss  of  C02  from  the 


■ • 


■ 


• - - V 


J ; . . 

- - 


. 

* ’ 


10. 


limestone  in  the  ore.  This  should  be  very  close  to  the  true 
value  since  the  first  residue  was  no  heated  to  such  a temp- 
erature that  this  difference  might  represent  a loss  in  weight 
from  the  decomposition  of  CaS©4.  In  fact  when  this  suppos- 
ition was  checked  by  the  direct  analysis  fro  sulfate  by  pre- 
cipitation with  BaC12,  the  weight  of  Ba  S04  from  a one  gram 
sample  of  the  ore  was  .1321  representing  7.69  percent  CaS04. 


. ' 


11. 


THE  LEACHING  PROCESS. 

As  has  been  previously  stated,  the  leaching  process 
consists  in  dissolving  the  sulfur  out  of  the  ore  by  means  of 
carbon  disulfide  from  which  solution  the  sulfur  is  removed 
upon  the  evaporation  of  the  solvent. 

The  study  of  this  method  of  production  presented 
several  definite  problems.  Namely,  the  determination  of 
the  following  factors: 

1.)  The  effect  of  the  fineness  of  the  ore  upon  the 
percent  of  sulfur  extracted. 

2)  The  volume  of  carbon  disulfide  necessary  per 
unit  of  ore. 

3.  ) The  amounts  of  sulfur  dissolved  by  succeeding 
portions  of  the  solvent. 

4. )  The  weight  of  the  solvent  held  by  the  sulfur, 
and  the  means  of  removing  the  last  traces  of  carbon  disulfide 
from  the  final  product. 

5. )  The  percent  loss  of  carbon  disulfide  through  the 

process . 

6.  ) The  amount  of  heat  required  by  the  process,  and 
the  means  of  producing  that  heat. 

7.  ) The  apparatus  necessary  to  carry  out  the  extract- 
ion efficiently,  and  the  probable  cost  of  that  apparatus. 

8.  ) The  cost  of  labor. 

In  the  line  of  the  first  of  these  problems  mention- 
ed, the  sulfur  was  extracted  from  three  one -hundred  gram 


' o 


* ■ i J.  t «■»... . . ^ 

* r ■>  .. 

. 


. 

. 


. 


' ' - . ■ ' . 

. ' w ■'  ' V • . 

. 


12. 


samples  of  the  ore.  That  Is,  from  the  finely  ground,  the  pea 
size,  and  the  egg  size.  In  each  case,  200  cc.  of  the  solvent 
was  used,  and  the  extraction  was  carried  out  in  a sealed  jar. 
The  finely  ground  material  of  course  went  into  solution  much 
more  rapidly  than  in  either  of  the  succeeding  cases,  hut  in 
each  case,  the  sulfur  product  weighed  the  same,  namely  57 
grams.  The  failure  of  the  solvent  to  remove  all  the  sulfur 
was  probably  due  to  an  equilibrium  effected  in  each  case  be- 
tween the  solution  and  the  solvent,  due  to  the  fact  that 
successive  portions  of  the  solvent  were  not  used.  The  exper- 
iment however  was  satisfactory  in  that  it  indicated  that  the 
fineness  of  the  ore  effects  only  the  time  element  in  the 
extraction,  and  showed  that  the  ore  is  sufficiently  porous 
to  allow  complete  disintegration  by  the  solvent.  In  all  three 
cases  the  residue  appeared  finely  divided  in  the  bottom  of 
the  jar  at  the  end  of  an  hour  period. 

The  sulfur  was  removed  from  the  solvent  by  allowing 
the  pregnant  solution  to  drop  slowly  upon  steam  heated 
watch  glasses.  No  attempt  was  made  at  this  time  to  recover 
the  solvent.  The  sulfur  which  remained  on  the  watch  glass 
was  scraped  off  from  time  to  time  in  order  that  the  extract  ion 
might  be  as  complete  as  possible. 

In  the  determination  of  the  amounts  of  sulfur  extracted 
by  succeeding  portions  of  the  solvent, and  the  percent  loss 
of  carbon  disulfide,  the  apparatus  shown  in  figure  1.  was 
constructed.  This  consisted  of  a 500cc.  distilling  flask  (A.) 


13. 


14.. 


connected  with  the  500cc.  separatory  funnel  (B.)  in  the  stem 
of  which  was  placed  some  glass  wool  to  act  as  a filter  and 
allow  only  the  pregnant  solution  to  pass  through  into  the 
flask  below.  A and  B were  both  weighed  before  the  deter- 
mination, after  which  200  grams  of  the  pea  sized  ore  was 
placed  in  B.  The  solvent  was  then  introduced  in  portions 
of  lOOcc.  When  each  lOOcc.  had  remained  in  contact  with  the 
ore  for  ten  minutes,  it  was  then  run  slowly  into  the  distill- 
ing flask  (A. ) from  which  the  carbon  disulfide  was  distilled 
into  the  recovering  chamber  (C.).  After  each  portion  had 
been  distilled  over,  the  weights  of  A and  B were  taken,  and 
the  volume  of  solvent  recovered  was  noted. 

The  increase  in  the  weight  of  A of  course  represent- 
ed the  amount  of  sulfur  extracted  by  the  portion  of  solvent 
recovered  in  the  bottle(0.}.  Since  the  change  in  weight  of 
the  separatory  funnel  (B.)  was  in  each  case  due  to  a loss 
of  sulfur  and  an  addition  of  carbon  disulfide,  the  amount  of 
the  solvent  which  remained  suspended  in  the  ore  was  determin- 
ed by  subtracting  the  total  weight  of  sulfur  in  the  flask 
(A.)  from  the  total  original  weight  of  the  funnel  (B.),  which 
it  is  evident  would  give  the  weight  of  the  funnel  in  case 
none  of  the  solvent  had  been  held  by  the  ore.  This  theor- 
etical weight  without  the  carbon  disulfide  then  subtracted 
from  the  actual  weight  of  (B. ) would  indicate  the  weight 
of  solvent  held  by  the  ore.  This  weight  is  shown  in  column 
six  of  table  1.  Four  portions  of  lOOcc.  each  were  used. 


' 

• * 


r 


...  v 


C D 


J 


* 


15 


TABLE  ONE. 

!•  2.  3.  4.  5.  6. 

Vol.l.  Vol.2.  Wt.  B.  Wt.  A.  Wt.  S.  Wt.  CS2  remain- 


— — J-xiK* 

143.5 

343.5 

204.0 

lOOcc . 

50cc . 

375.0 

230.0 

26  g. 

57.5 

lOOcc . 

78cc  • 

359.0 

265.0 

35  g. 

76.5 

lOOcc  * 

102cc . 

315.0 

300 

35  g. 

67.5 

lOOcc . 

70cc. 

328.0 

320. 

20  g. 

100  g - 79cc. 

400cc . 

379cc. 

116  g. 

579 

5.25/3  loss  58  g.  per  100  grams  — 

98.3^  efficient. 


16. 


In  the  introduction  of  the  fourth  portion,  the  glass  wool 
became  misplaced  from  the  bottom  of  the  funnel,  so  it  was 
thought  best  to  stop  the  proceedure  in  order  that  the  results 
might  be  most  accurate.  Accordingly  the  apparatus  was  re- 
arranged, and  the  100  grams  of  carbon  disulfide  remaining 
in  (B.)  was  distilled  into  (C.).  From  the  calculated  value 
of  100  grams  or  80cc.  of  carbon  disulfide,  79c c.  were  recov- 
ered. It  is  quite  possible  that  this  79cc.  represented  the 
total  held  rather  than  80cc.  since  the  latter  was  determined 
by  a round  about  calculation.  Thus,  it  seems  quite  evident 
that  it  is  possible  to  remove  practically  all  the  carbon 
disulfide  from  the  residue. 

It  may  be  seen  from  the  table  that  despite  the  fact 
that  the  apparatus  was  of  a very  crude  character,  the  loss 
of  carbon  disulfide  was  only  5.25%,  and  the  sulfur  removed 
from  the  200  gram  sample  weighed  116  grams  indicating  that 
the  extraction  was  98.3%  efficient  in  that  58  grams  of  the 
available  59  grams  of  sulfur  in  each  100  grams  of  ore  had 
been  removed.  In  all  weighings,  the  flasks  were  immediately 
sealed  upon  separation  from  the  remainder  of  the  apparatus, 
and  every  precaution  was  taken,  but  it  is  very  evident  that 
a considerable  amount  of  the  solvent  could  be  lost  in  hand- 
ling. It  appears  therefore  that  ing  ce^^rcial  plant  the 
loss  should  not  exceed  one  percent.  The  table  also  indicates 
from  a study  of  columns  2 and  5 that  the  weight  of  sulfur 
carried  by  the  solvent  decreased  with  each  succeeding  portion. 


17. 


In  fact  if  the  weights  of  sulfur  carried  by  the  solvent 
were  calculated  in  each  case  to  a corresponding  weight 
carried  by  lOOcc.,  the  weights  would  be  54,  45,  34,  and 
28.6  grams  respectively.  It  thus  appears  that  a very  eff- 
icient extraction  could  be  carried  out  with  approximately 
200cc.  of  the  solvent  for  every  100  grams  of  the  sulfur 
product  since  the  solvent  could  be  run  through  a series  of 
autoclaves  in  such  a manner  that  no  carbon  disulfide  would 
enter  the  distilling  chamber  until  completely  saturated. 

It  has  been  claimed  as  a serious  difficulty  to  the 
use  of  the  leaching  process  that  the  final  product  at  best 
contains  a considerable  amount  of  carbon  disulfide  which 
decreases  the  value  of  the  product.  (1.)  To  test  the  re- 
liability of  this  assertion,  50  grams  of  sulfur  prepared 
by  this  leaching  process  were  accurately  weighed  out  in  a 
lOOcc.  beaker  of  known  weight.  This  beaker  was  then  kept 
at  a temperature  of  40  to  50  degrees  centigrade  for  twenty 
four  hours  during  which  time  the  sulfur  was  stirred  several 
times.  During  the  first  hour  of  heating  the  sulfur  smelled 
quite  noticably  of  the  solvent,  but  that  odor  had  completely 
disappeared  within  the  second  hour.  At  the  end  of  this  per- 
iod the  beaker  was  weighed  and  indicated  a loss  of  .1  gram  or 
0.2$  due  probably  to  carbon  disulfide.  In  order  to  show  that 
the  loss  had  not  been  due  to  slow  oxidation  of  the  sulfur, 
the  beaker  was  heated  until  the  following  day,  but  no  further 

(1.)  Journal  of  Soc.  of  Chem  Ind.  660.5  J.S.  226,  pl8. 


10. 


loss  of  weight  was  indicated.  It  thus  appears  that  the  car- 
hen  disulfide  held  by  the  product  is  relatively  slight  and  is 
easily  eliminated.  The  brimstone  thus  produced  when  ground 
would  sell  for  approximately  fifty  dollars  a ton  in  the  states 
surrounding  Utah. 

The  apparent  difficulties  surrounding  the  adoption 
of  the  leaching  process  are: 

1. )  The  necessity  of  a plant  for  the  manufacture  of 
carbon  disulfide. 

2. )  The  complication  of  plant  required  to  carry  out 
the  extraction. 

3. )  The  high  quality  of  labor  necessary. 

4. )  The  lack  of  a large  supply  of  water  at  the  plant. 

The  present  equipment  of  the  Utah  plant  includes  a 

quite  inefficient  carbon  disulfide  furnace , parts  of  which 
have  already  burned  out  at  least  once.  Although  the  destroy- 
ed parts  were  replaced  so  that  operations  could  be  continued, 
it  appears  that  the  type  of  furnace  is  obsolete  and  should  be 
replaced  at  the  first  opportunity  by  an  electric  furnace 
similar  to  that  used  by  the  manufacturers  of  carbon  disulfide 
at  Pen  Yan,Penn. 

Next,  this  process  would  require  storage  room  and 
pumps  to  handle  the  solvent,  huge  tanks  or  leachers  in  which  to 
digest  the  ore,  and  evaporators  in  which  the  sulfur  product 
is  deposited.  The  condensers  used  in  the  manufacture  of  the 
solvent  could  of  course  also  be  used  in  recovering  the  carbon 


12 


disulfide.  It  seems  highly  probable  that  electric  evaporators 
could  be  used  thus  eliminating  the  necessity  of  the  steam 
boilers  which  would  be  used  in  the  case  that  steam  evaporators 
were  used.  This  might  also  be  an  advantageous  change  since 
this  type  of  evaporator  would  eliminate  the  use  of  a large 
amount  of  water  which  is  not  available  at  the  plant  at  the 
present . 

It  might  appear  that  due  to  the  necessity  for  the 
accurate  manipulation  of  many  valve3  which  would  have  to  be 
opened  and  closed  in  a certain  and  proper  order,  that  there 
would  be  a considerable  increase  in  the  cost  of  labor.  It  is 
true  that  a good  deal  of  responsibility  would  have  to  be  placed 
upon  the  operators  of  the  apparatus  because  of  the  great  care 
which  would  have  to  be  taken  in  handling  the  highly  inflamable 
solvent,  and  that  this  type  of  labor  would  cost  more  per 
individual.  However,  the  fact  should  not  be  overlooked  that 
this  labor  would  be  less  mobile  than  the  less  skilled  or  res- 
ponsible men,  and  therefore  the  decrease  in  the  labor  turnover 
would  considerably  offset  the  increase  in  the  individual  wages. 
Also  it  seems  that  this  process  would  require  fewer  men  to 
handle  the  equipment  than  either  the  retorting  or  the  roast- 
ing processes,  since  the  leaching  process  could  be  most  nearly 
machine  controled.  It  therefore  seems  highly  probable  that 
the  cost  of  labor  for  this  process  would  be  smaller  rather 
than  larger  than  that  required  by  other  methods. 


. 


. 

l ■ • ;•  J. 


, . ; 

' 

. 


- ; ■ 


r— ■■■  -■  - - 

THE  ROASTING  PROCESS. 

In  view  of  the  difficulties  which  have  been  exper- 
ienced in  the  steam  retorting  process,  and  in  the  leaching 
process,  and  considering  the  fact  that  sulfur  vaporizes  at 
450  degrees  centigrade,  it  seemed  possible  that  a clean  cut 
and  efficient  extraction  might  be  effected  by  heating  the  ore 
in  a closed  retort  to  a temperature  just  above  the  boiling 
point  of  sulfur.  In  the  usual  manner  of  producing  flowers 
of  sulfur,  the  brimstone  is  melted  and  run  slowly  into  a 
retort  below  from  which  it  is  vaporized  and  collected  in  the 
form  of  flowers  in  an  adjacent  chamber.  This  contemplated 
roasting  process  would  however  afford  a means  of  producing 
this  much  more  valuable  form  of  the  product  direct  from  the 
ore,  and  should  thus  save  a considerable  expense.  Crude 
brimstone  is  worth  approximately  one  third  the  value  of 
flowers  of  sulfur. 

The  fact  that  electric  power,  produced  by  hydraulic 
means,  is  available  at  the  plant  makes  it  seem  probable  that 
an  electric  furnace  could  easily  be  designed  which  would  be 
very  efficient  due  to  the  relative  low  cost  of  power  produced 
by  water  falls. 

A type  of  furnace  for  this  extraction  might  be  con- 
structed similar  to  the  furnaces  at  Pen  Yan,  Penn.  (1.)  used 
in  the  production  of  carbon  disulfide.  That  is,  a large 
vertical  affair  with  the  heat  applied  from  the  center.  The 
ore  would  be  introduced  from  the  top  of  the  surrounding 

(1.)  J.  Wright,  Electric  Furnaces  and  Industrial  Appli- 
cations 669.8  W93e  Report  on  Pen  Yan  Furnaces. 


- 

. 

1 

- 


. 


' . 
. •'  • I 


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. 


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- ■ . ; . : •. 

. 


F 

. 


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. 


21 


chambers  very  similarly  to  the  means  of  introducing  the  mater- 
ials into  the  ordinary  blast  furnace.  These  outer  portions 
of  the  furnace  would  serve  the  double  purpose  of  melting  the 
greater  portion  of  the  sulfur  out  of  the  ore,  and  utilizing 
the  heat  radiating  from  the  central  portion  of  the  furnace. 

In  the  central  section  of  the  furnace  the  heat  would  be 
greatest  and  sufficient  to  drive  the  product  into  an  adjacent 
chamber  of  the  ordinary  type  used  to  condense  the  vapors  in 
the  manufacture  of  flowers  of  sulfur  by  the  present  system. 

Such  a type  of  furnace  would  however  be  very  difficult 
to  construct  in  the  laboratory;  so  consideration  was  given 
the  possibility  of  using  a relatively  simple  furnace  such  as 
used  quite  widely  in  the  coke  and  gas  industry. 

Accordingly  two  distilling  retorts  were  constructed. 

The  first  from  an  iron  pipe  one  and  one  half  inches  in  diam- 
eter and  ten  inches  long.  This  retort  was  sealed  at  the  top 
and  bottom  by  removable  caps.  At  about  one  and  one  half  inches 
from  the  top,  a connecting  tube  was  inserted.  This  tube  con- 
sisted of  a one  half  inch  pipe  one  and  one  half  feet  in  length. 
The  opposite  end  of  this  tube  was  then  introduced  into  the 
condensing  chamber  which  was  made  from  a common  tin  plated 
cracker  box  of  one  foot  dimensions  carefully  sealed  with 
asbestos  paper.  The  second  retort  was  similarly  constructed, 
but  was  made  of  two  inch  piping  rather  than  one  and  one  half 
inch  and  was  only  six  inches  in  length. 


The  heat  required  for  the  distillation  was  furnished 


. 


* 

. 

• 

* 

' 


■ ■. 

, 

* 


22 


from  an  ordinary  Case  furnace  capable  of  giving  a temperature 
of  1000  degrees  centigrade.  On  two  occasions  this  furnace 
was  replaced  by  an  electric  resistance  furnace  in  which  the 
one  and  one  half  inch  pipe  was  snugly  fitted,  and  in  one  trial, 
the  tin  condensing  chamber  was  replaced  by  a four  or  five  liter 
Florence  flask  which  enabled  the  operator  to  watch  the  progress 
of  the  distillation. 

In  the  first  trial,  considerable  difficulty  was  exper- 
ienced from  the  melted  sulfur  leaking  through  the  pipe  connect- 
ions which  were  not  sufficiently  sealed.  This  was  remedied  by 
treatment  with  white  lead.  In  the  next  succeeding  efforts, 
the  inclosed  sulfur  boiled  over  and  into  the  condensing  chamber 
before  the  distillation  was  completed  , and  in  one  instance 
the  condensing  chamber  exploded.  This  was  considered  due  to 
the  contact  of  the  escaping  fumes  of  sulfur  with  the  Bunsen 
flames  which  were  used  to  heat  the  connecting  tube  in  order 
that  the  fumes  would  not  condense  in  that  tube  before  they 
reached  the  chamber.  To  prevent  a reoccurance  of  such  an 
explosion,  a thick  sheet  of  asbestos  paper  was  placed  between 
the  flames  and  the  condensing  chamber. 

In  the  most  successful  attempt,  one  hundred  grams  of 
the  ore,  pea  sized,  were  used,  which  weight  filled  the  retort 
number  one  only  one  third  full.  In  addition  the  whole  appar- 
atus was  so  placed  that  the  connecting  tube  made  an  angle 
of  about  thirty  degrees  with  the  horizontal  in  order  that  any 
liquid  sulfur  which  reached  the  tube  would  flow  back  into 


■ • 


* * 


j ■ 


:• 


. 


■>  . 


23 


■■  ■■  —■■===  11  1,1  " ""  " ‘ 

the  retort  rather  than  into  the  condensing  chamber.  The 
highest  temperature  reached  was  600  degrees  centigrade.  It 
seemed  most  important  that  the  temperature  should  be  slowly 
increased  after  the  melting  point  of  sulfur  was  reached. 

It  appears  that  such  a proceedure  prevents  the  ash  in  the 
ore  from  being  shaken  in  the  retort  and  thence  into  the 
condensing  chamber  with  the  final  product.  In  this  instance, 
all  precautions  learned  in  the  previous  trials  were  observed. 
The  product  appeared  identical  with  the  commercial  product 
of  flowers  of  sulfur,  and  burned  completely  when  tested  in 
a small  porcelain  crucible. 

The  main  difficulty  appeared  to  result  from  the 
boiling  over  of  the  sulfur  which  made  it  possible  to  use 
only  a small  amount  of  ore  at  one  time.  However  this  exper- 
iment proved  conclusively  that  the  valuable  flowers  of  sulfur 
can  be  produced  by  this  direct  method. 

A furnace  similar  to  those  used  at  Pen  Yan  would  seem 
quite  possible  for  use  with  sulfur  alone.  In  designing  such 
a furnace  two  specific  principles  should  be  kept  in  mind  which 
would  result  in  high  efficiency  if  adhered  to;  The  first 
and  principal  aim  should  be  toward  making  possible  the  contin- 
uity of  furnace  action,  whereby  the  plant  may  be  worked  day 
and  night  with  a consequent  gain  in  efficiency.  Secondly, 
there  should  be  some  device  by  which  the  raw  materials  may 
be  heated  prior  to  their  introduction  into  the  furnace,  thereby 
involving  a lesser  expenditure  of  heat  energy  and  electrical 


2A 


power  than  would  otherwise  be  necessary.  (1.) 

SUMMARY. 

It  has  been  shown  that  the  steam  retorting  method  should 
not  be  considered.  Likewise,  the  method  of  mining  used  in 
Louisiana  and  Texas  would  be  impossible,  first  because  a 
great  portion  of  the  Utah  ore  is  near  the  surface,  but  most 
important  because  this  method  is  essentially  only  a modification 
of  the  steam  retorting  process,  and  would  therefore  be  like- 
wise inefficient.  A choice  must  then  be  made  between  the 
roasting  and  the  leaching  processes.  It  appears  from  the 
previous  discussion  that  both  can  be  carried  out  satisfactorily. 

Despite  the  apparent  success  of  the  experiment  carried  out  with 
the  leaching  process,  it  seems  that  due  to  the  greater  value 
of  flowers  of  sulfur,  the  roasting  process  would  be  most 
advisable.  Economic  conditions  in  the  vicinity  of  Utah  re- 
garding the  ease  of  sale  and  shipment  of  the  two  varieties 
should  however  also  be  duly  considered,  and  that  process 
should  be  chosen  which  would  give  the  most  certain  and  steady 
income.  For  this  reason  it  appears  that  the  roasting  process 
would  be  most  satisfactory  in  that  both  brimstone  and  flowers 
of  sulfur  could  be  produced,  by  this  method.  The  brimstone  in 
this  case  would  be  obtained  by  melting  a portion  of  the  flow- 
ers. This  latter  step  should  however  be  effected  only  in  the 
event  that  the  quantity  of  flowers  produced  exceeded  the  de- 
mand for  that  substance. 

In  the  case  that  it  might  be  found  advisable  to  con- 

(1.0)  J.  Wright  , Elect.  Furnaces  and  Ind.  Applications 
669.8  W93c. 


25. 


tinue  the  use  of  the  present  leaching  equipment  rather  than 
install  the  several  furnaces  which  would  be  required  to 
satisfactorily  carry  out  the  roasting  process,  the  flowers 
of  sulfur  could  be  produced  from  the  brimstone  of  the  leach- 
ing process  in  a single  furnace  of  the  Pen  Yan  type  which  could 
be  so  designed  that  the  carbon  disulfide  could  be  manufactured 
in  this  same  furnace  at  such  times  as  it  would  otherwise  be 
idle.  The  outer  portions  could  easily  be  so  designed  that 
the  furnace  action  would  be  continuous. 


2£. 


UTILIZATION . 

As  has  been  recognized  in  the  above  discussion,  the 
market  for  sulfur  is  divided  among  five  separate  types  of 
the  element.  Namely: 

1.  ) Crude  brimstone. 

2. )  Lump  brimstone  (refined) 

3. )  Stick  brimstone  (refined) 

4. )  Ground  sulfur  (brimstone) 

5.  ) Flowers  of  sulfur. 

Next,  there  are  threedistinct  types  of  industries 
in  which  these  types  of  the  product  are  widely  used,  i.e. 

1.)  The  general  manufacturing  industries,  2.)  Explosives 
industry,  3.)  The  agricultural  industries. 

Most  important  with  respect  to  the  quantity  of  sulfur 
used  by  the  first  class  are  the  paper  and  sugar  industries. 
Producers  of  these  substances  use  large  quantities  of  sulfur 
for  bleaching  purposes.  In  the  several  states  surrounding 
Utah,  there  are  many  sugar  beet  factories.  These  factories 
however  use  crude  sulfur  entirely;  so  should  not  be  considered 
too  seriously  as  consumers  in  case  the  roasting  process  is 
decided  upon. 

Especial  efforts  should  be  made  to  produce  and  maintain 

a market  for  flowers  of  sulfur  with  the  powder  plants  and 

the  fruit  ranches  in  the  northwestern  states.  This  would  be 
3.  dv  i ^ sib  1 & 

particularly  since  it  appears  that  in  these  states  the  com- 
petition with  sulfur  products  from  the  southern  states  and 
from  Japan  would  be  at  a minimum.  According  to  the  present 


. 


, 


. 

■ - ■ , 

. • 


. . 3 ; 

. 

. 

■ 

. 


‘IC 

. 

23L 


market  conditions,  it  is  evident  that  flowers  of  sulfur  should 
show  a profit  to  the  manufacturers  of  at  least  two  and  one  half 
times  that  which  would  be  realized  upon  brimstone.  It  would 
seem  safe  to  predict  that  the  sulfur  market  will  not  change 
further  from  the  results  of  the  recent  war,  and  that  a steady 
market  can  be  maintained  through  the  sale  of  the  products  to 
the  numerous  ranches  in  the  vincinity  of  Utah. 

Additional,  though  less  extensive  fields  for  the  sale 
of  sulfur  may  be  found  through  contact  with  the  manufacturers 
of  sulfur  dioxide,  sulfuric  acid,  carbon  disulfide,  matches, 
fireworks,  sprays,  germicides,  and  sulfur  dyes;  but  it  is 
most  important  that  relations  be  first  established  with  the 
larger  users  in  order  that  a steady  market  may  be  maintained. 


